刀具磨损在线检测及刀具寿命实时跟踪技术在FMS中应用

刀具磨损在线检测和刀具寿命实时跟踪是柔性制造系统(FMS)的关键技术之一,通过分析刀具磨损在线检测原理,形成了适合于FMS刀具磨损检测的方案和具体实施办法,通过探讨刀具寿命的主要影响因素,提出了使用雷尼绍NC4非接触式刀具磨损检测系统进行刀具寿命监控的措施,在此基础上,开发了刀具寿命跟踪管理系统。研究成果提高了刀具磨损检测和刀具寿命管理的准确性与控制效率,有效提升了FMS工件加工合格率和加工精度。     

双刀架曲轴数控车削在线测量及自动补偿的实现

为提高曲轴数控加工自动化程度,采用了双刀架曲轴数控加工与在线检测集成的方法,开发了上、下刀架刀具磨损自动补偿子程序.实际应用表明在线尺寸检测及自动补偿技术改善了加工质量和提高了加工效率.     

带磨损补偿功能的刀具状态在线检测技术研究

利用多个传感器在线采集刀具状态数据,建立了刀具状态在线检测系统。该系统具有刀具磨损补偿的功能。     

数控车床全闭环控制系统的研究与分析

将在线检测技术和数控技术结合起来对经济型数控车床进行全闭环设计。在线检测技术使加工中的测量仪器与机床、刀具、工件组成一个闭环系统,工件加工过程中实时测量工件的尺寸,再根据测得的实际尺寸来调整刀具的进给量,从而实现真正意义的全闭环控制。此装置的研究和设计将对经济型数控机床改造有积极的影响和重要的意义,同时对数控机床的发展也有较好的推动与启示作用。     

精镗刀具的自动补偿机构

精镗加工时,刀尖磨损所造成的工件孔径误差,可以用图1所示尺寸控制系统进行补偿。量头6对已加工孔5进行自动测量,所得数据输入控制装置7。在与给定的调整值比较后作出判断:如需补偿,则由7发出补偿信号给补偿装置4,后者通过镗头使镗刀产生径向微量位移。这样,在加工下一工件时,刀具磨损所造成的工件孔径误差便基本上得到了补偿.采用尺寸控制系统,可使一批工件的孔径分布在公差带中某一尺寸范围内,因此可有效地提高工件的尺寸精度。尺寸控制系统只能补偿刀具磨损所引起的孔径变化,以及精镗长孔时因刀具磨损     

刀具损伤的在线检测技术

刀具损伤的在线检测技术岳阳市工业局刘阳春使用刀具进行机械加工过程中，如果刀具出现磨损、损伤、打刀、崩刃等情况，会降低产品的尺寸精度及增大表面粗糙度。为了加工出符合精度要求且经济性好的产品，必须对加工工艺、刀具、工件进行在线检测与监控。另外，为了保证Ｆ...     

基于振动测试的数控机床刀具磨损监测方法

为了通过特性分析直接判断数控机床刀具的工作状态,以实现柔性制造系统的研究,在刀具磨损的多种在线监测方法中采用振动测试的监测方法,对DL20MH数控车削中心的YG8硬质合金刀头进行在线监测,分别在不同的刀具磨损阶段实时监测其磨损信号,通过时域分析、频域分析和传递函数分析相结合的方法进行数据处理,并对照被加工工件的表面粗糙度和通过显微镜下观察刀刃的实时变化情况,对其进行分析处理,得出刀具的实时变化情况及被加工工件的粗糙度与理论数据基本吻合并呈现出一定的趋势,从实频域分析数据中也可以直观地判断刀具的磨损状态,测试结果与实际情况吻合,从而验证了振动测试是适合刀具磨损在线监测研究的.     

异构数据融合的CNC刀具磨损状态在线识别方法

针对CNC在线视觉识别刀具磨损状态信息源单一、易受干扰导致识别准确率低、可靠性差的问题,提出一种基于异构数据融合的识别方法。采用自主研发的在线视觉检测装置和TCP/IP通信技术,获取工件切痕图像和机床内置传感器数据;基于与磨损相关的异构数据特征信息,利用支持向量机构建初步识别模型;使用邓熵与加权证据理论融合初步识别结果,得到刀具磨损状态最终识别结果。研究结果表明,该识别方法对测试集的识别结果准确率达到100%,且识别结果的均方误差最小,有较强的抗干扰能力。     

基于FANUC用户宏程序的刀具磨损补偿问题研究

针对刀具通过调整几何补偿的方法进行刀具磨损补偿时,初始值丢失需重新按步骤获取补偿量增加占机时间的问题,通过分析刀具磨损规律,提出一种对新刀具从零磨损开始补偿,而后根据刀具磨损状态调整补偿量的方法。利用FANUC系统用户宏程序功能,开发的刀具磨损补偿子程序在HTM-TC20数控车削中心上进行验证,有效解决了由于刀具磨损使加工工件过大和刀具磨损补偿问题,减少了占机时间,提高加工效率。该方法也可以移植到Z轴的磨损补偿校正中。     

基于在线检测技术的批量装夹加工精度控制

针对结构相同的批量零件采用多工位组合装夹数控加工时,由于刀具磨损造成的误差得不到准确同步检测的问题,探索应用UG软件CMM模块,对零件批量组合装夹加工过程进行线上检测。规划测头检测动作路径,对加工工件的多个几何要素进行检测,编制调用系统检测宏程序,运用宏程序条件转移功能快速侦测刀具磨损造成的误差,对装夹在数控机床G54～G59不同工件坐标系的零件进行及时调整刀具补偿参数、修正误差。结果表明,在线检测技术的应用可以有效拓展数控机床的功能,显著提高批量生产零件的加工质量和效率。     

数字孪生驱动的数控铣削刀具磨损在线监测方法

针对数控铣床不断老化导致刀具磨损预测模型误差较大,加工过程中动态数据难以在线采集等问题,提出一种数字孪生驱动的刀具磨损在线监测方法。采用神经网络对加工过程中的多源数据进行特征提取,建立考虑机床老化的刀具磨损时变偏差量化模型,并在此基础上提出数控铣削刀具磨损的在线预测方法;开发了面向刀具磨损的数控铣削数字孪生系统,在线感知加工过程中的动态数据并实时仿真刀具磨损过程;最后,将该方法应用于实际加工中并与其他的预测方法进行了对比,结果表明该方法有效降低了机床老化带来的误差,实现了刀具磨损的精确预测。     

数控机床热变形误差研究及补偿应用

热变形误差是影响机床加工精度的重要因素之一,通过误差补偿的方法可以提高机床的加工精度。研究了通过实时补偿热变形误差提高数控机床加工精度的方法,阐述了热误差的基本原理,介绍了热误差的测量方法。采用模糊聚类的方法来布置测温点,利用多元线形回归方法建立了机床热变形与温升之间的数学模型。在PLC补偿系统的作用下,在加工过程中对XH718数控机床进行实时补偿。实验结果表明补偿效果很好。     

An online optical system for inspecting tool condition in milling of H13 tool steel and IN 718 alloy

Tool wear adversely affects surface integrity due to higher cutting forces and temperatures. However, an accurate and efficient tool wear measurement is a challenging problem. The traditional direct tool wear measurement methods such as optical microscope and scanning electron microscope (SEM) leads to error of tool reassembly, tool orientation, and low accuracy, while the indirect measurement methods cause poor accuracy. In this paper, tool wear phenomena in milling of tool steel AISI H13 and superalloy Inconel 718 have been studied. A novel online optical system has been developed to integrate with a CNC machine to directly inspect and measure tool wear conditions in milling which minimizes the above-mentioned measurement errors in traditional methods. The evolutions of tool flank wear of PVD-coated inserts in end milling of the two materials were inspected to demonstrate the function of the optical measurement system. The tool wear evolution versus cutting time were obtained and examined. The characteristic images of fast tool wear in milling of Inconel 718 were captured using SEM and compared with the optical images to estimate flank wear. Three basic modes of tool wear—flank wear, nose wear, and crater wear—were compared and analyzed. A two-parameter method has been developed to evaluate both flank wear and nose wear with respect to cutting time in milling of Inconel 718. The advantages of the on-line optical tool inspection system were discussed.     

基于径向基函数神经网络的铣刀磨损监控技术的研究

提出一种基于径向基函数神经网络的铣刀磨损监控方法,径向基函数神经网络的输出是刀具磨损的具体值,这样有利于对刀具磨损进行各种实时补偿。实验表明,利用径向基函数神经网络进行状态识别可对小型立铣刀的磨损进行监控,能够取得良好的效果,同时证明RBF网络的训练速度优于BP网络。     

Data acquisition and monitoring in machine tools with CNC of open architecture using internet

This paper presents a proposed system for data acquisition and monitoring of manufacturing process in machine tools with CNC of open architecture, using the Internet. It was applied to evaluate workpiece dimension and, indirectly, tool wear, as well as sharing shop floor information, in real time, in any place through Intranet and/or Internet, aiding the whole integration of the manufacturing system. The proposed system was developed and tested initially in a CNC lathe with open architecture. However, it can be extended to other machines and processes, lines or cells of mass production as well. In the first experiments, the system was capable of maintaining uniform, within a closer tolerance, the diameter of a batch of 30 workpieces, changing from an ISO IT13 quality to ISO IT09. It was also possible to share on-line information about the process, production and technological parameters, by Intranet/Internet, using only a HTML page navigator .     

Assessment and visualisation of machine tool wear using computer vision

Tool wear monitoring is an integral part of modern CNC machine control. Cutting tools must be periodically checked for possible or actual premature failures, and it is necessary to record the cutting history for a tool’s full life of utilisation. This means that an on-line monitoring system would be of great benefit to overall process control in manufacturing systems. Computer vision has already shown promise as a candidate technology for this task. In this paper, we describe the use of digital image processing techniques in the analysis of images of worn cutting tools in order to assess their degree of wear and thus remaining useful life. It is shown that a processing strategy using a variety of image texture measures allows for effective visualisation and assessment of tool wear, and indicates good correlation with the expected wear characteristics.     

面向数控机床的远程在线监测与故障诊断系统的研究

在分析了数控机床远程在线监控与故障诊断系统的需求的基础上，从框架体系结构和技术体系结构两个不同方面详细地介绍了满足面向数控机床的远程在线监测与故障诊断系统的体系结构。最后研究了系统的实现方法，并建立了原型系统。     

基于切削力信号的钻头磨损状态实时监测

研究了钻削过程中刀具在线磨损状态特征信号的提取方法。以轴向力和扭矩为监测信号,在普通钻床上建立起相应的实时信号数据采集系统,通过对信号进行幅域和频域分析,提取了特征信号随刀具磨损量增加的变化规律,为实现机械加工过程刀具状态的智能识别提供了依据。试验结果表明,该方法具有较好的抗干扰能力和较高的识别精度。     

Three-dimensional tool radius compensation for multi-axis peripheral milling

Few function about 3D tool radius compensation is applied to generating executable motion control commands in the existing computer numerical control (CNC) systems. Once the tool radius is changed, especially in the case of tool size changing with tool wear in machining, a new NC program has to be recreated. A generic 3D tool radius compensation method for multi-axis peripheral milling in CNC systems is presented. The offset path is calculated by offsetting the tool path along the direction of the offset vector with a given distance. The offset vector is perpendicular to both the tangent vector of the tool path and the orientation vector of the tool axis relative to the workpiece. The orientation vector equations of the tool axis relative to the workpiece are obtained through homogeneous coordinate transformation matrix and forward kinematics of generalized kinematics model of multi-axis machine tools. To avoid cutting into the corner formed by the two adjacent tool paths, the coordinates of offset path at the intersection point have been calculated according to the transition type that is determined by the angle between the two tool path tangent vectors at the corner. Through the verification by the solid cutting simulation software VERICUTwith different tool radiuses on a table-tilting type five-axis machine tool, and by the real machining experiment of machining a soup spoon on a five-axis machine tool with the developed CNC system, the effectiveness of the proposed 3D tool radius compensation method is confirmed. The proposed compensation method can be suitable for all kinds of threeto five-axis machine tools as a general form.